The thermodynamic properties of the ε phase of solid oxygen are studied by using the analytic mean field approach （AMFP）. Analytic expressions for the Helmholtz free energy, internal energy and equation of state of...The thermodynamic properties of the ε phase of solid oxygen are studied by using the analytic mean field approach （AMFP）. Analytic expressions for the Helmholtz free energy, internal energy and equation of state of solid oxygen have been derived based on the multi-exponential potential. The formulism for the case of double-exponential （DE） model is applied to the ε phase of solid oxygen. Its four potential parameters are determined through fitting the experimental compression data of the ε phase of solid oxygen. Numerical results of the pressure dependence of the volume calculated by using the AMFP are in good agreement with the original experimental data. This suggests that the AMFP is a useful approach to study the thermodynamic properties of the ε phase of solid oxygen. Furthermore, we predict the variation of the volume, lattice parameters and intermolecular distances with pressure, and some thermodynamic quantities versus volume, at several higher temperatures.展开更多
It is important to know whether the laws or phenomena in statistical physics for natural systems with non-adaptive agents still hold for social human systems with adaptive agents, because this implies whether it is po...It is important to know whether the laws or phenomena in statistical physics for natural systems with non-adaptive agents still hold for social human systems with adaptive agents, because this implies whether it is possible to study or understand social human systems by using statistical physics originating from natural systems. For this purpose, we review the role of human adaptability in four kinds of specific human behaviors, namely, normal behavior, herd behavior, contrarian behavior, and hedge behavior. The approach is based on controlled experiments in the framework of market-directed resource-allocation games. The role of the controlled experiments could be at least two-fold： adopting the real human decision-making process so that the system under consideration could reflect the performance of genuine human beings; making it possible to obtain macroscopic physical properties of a human system by tuning a particular factor of the system, thus directly revealing cause and effect. As a result, both computer simulations and theoretical analyses help to show a few counterparts of some laws or phenomena in statistical physics for social human systems： two-phase phenomena or phase transitions, entropy-related phenomena, and a non-equilibrium steady state. This review highlights the role of human adaptability in these counterparts, and makes it possible to study or understand some particular social human systems by means of statistical physics coming from natural systems.展开更多
Since the first demonstrations of nuclear magnetic resonance (NMR) in condensed matter in 1946, the field of NMR has yielded a continuous flow of conceptual advances and methodological innovations that continues today...Since the first demonstrations of nuclear magnetic resonance (NMR) in condensed matter in 1946, the field of NMR has yielded a continuous flow of conceptual advances and methodological innovations that continues today. Much progress has been made in the utilization of solid-state NMR to illuminate molecular structure and dynamics in systems not controllable by any other way. NMR deals with time-dependent perturbations of nuclear spin systems and solving the time-dependent Schrodinger equation is a central problem in quantum physics in general and solid-state NMR in particular. This theoretical perspective outlines the methods used to treat theoretical problems in solid-state NMR as well as the recent theoretical development of spin dynamics in NMR and physics. The purpose of this review is to unravel the versatility of theories in solid-state NMR and to present the recent theoretical developments of spin dynamics.展开更多
We study theoretically the electron transport properties in achiral carbon nanotubes under the influence of an external electric field E(t) using Boltzmann’s transport equation to derive the current-density. A negati...We study theoretically the electron transport properties in achiral carbon nanotubes under the influence of an external electric field E(t) using Boltzmann’s transport equation to derive the current-density. A negative differential conductivity (NDC) is predicted in quasi-static approximation i.e., ωτ 0 is equal to the amplitude of the AC electric field E1. The peak of the NDC intensity occurs at very weaker fields than that of superlattice under the same conditions. The peak intensity decreases and shifts to right with the increase in the amplitude of the ac field. This mechanism suppresses the domain formation and therefore could be used in terahertz frequency generation.展开更多
The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods t...The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods to address the cooling challenge for high-power devices in DCs.Hybrid nanofluid(HNF)has the advantages of high thermal conductivity and good rheological properties.This study summarizes the numerical investigations of HNFs in mini/micro heat sinks,including the numerical methods,hydrothermal characteristics,and enhanced heat transfer technologies.The innovations of this paper include:(1)the characteristics,applicable conditions,and scenarios of each theoretical method and numerical method are clarified;(2)the molecular dynamics(MD)simulation can reveal the synergy effect,micro motion,and agglomeration morphology of different nanoparticles.Machine learning(ML)presents a feasiblemethod for parameter prediction,which provides the opportunity for the intelligent regulation of the thermal performance of HNFs;(3)the HNFs flowboiling and the synergy of passive and active technologies may further improve the overall efficiency of liquid cooling systems in DCs.This review provides valuable insights and references for exploring the multi-phase flow and heat transport mechanisms of HNFs,and promoting the practical application of HNFs in chip-level liquid cooling in DCs.展开更多
High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-co...High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-corrected transmission electron microscopy constrain resolution.A machine learning algorithm is developed to determine the aberration parameters with higher precision from small,lattice-periodic crystal images.The proposed algorithm is then validated with simulated HRTEM images of graphene and applied to the experimental images of a molybdenum disulfide(MoS_(2))monolayer with 25 variables(14 aberrations)resolved in wide ranges.Using these measured parameters,the phases of the exit-wave functions are reconstructed for each image in a focal series of MoS_(2)monolayers.The images were acquired due to the unexpected movement of the specimen holder.Four-dimensional data extraction reveals time-varying atomic structures and ripple.In particular,the atomic evolution of the sulfur-vacancy point and line defects,as well as the edge structure near the amorphous,is visualized as the resolution has been improved from about 1.75?to 0.9 A.This method can help salvage important transmission electron microscope images and is beneficial for the images obtained from electron microscopes with average stability.展开更多
An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as t...An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as the amplitude of the liquid column oscillations increases,parametric oscillations of the interface are excited in the form of a standing wave located in the channel plane.In particular,depending on the interfacial tension,the standing waves have a frequency equal to that of liquid piston oscillations(harmonic response),or half of the frequency of oscillations of the liquid column in the channel(subharmonic response).The detected type of instability has a gravitational-capillary nature and is analogous to Faraday waves.The analysis of the overcritical dynamics of wave oscillations indicates that interfacial tension plays a crucial role in determining the type of parametric instability.At high interfacial tension,only synchronous(harmonic)wave modes are observed,and the threshold of the wave excitation is determined by the amplitude of piston oscillations of the liquid column.In this case,the oscillation acceleration does not play a role and has a small value in the threshold of the synchronous mode response.In the case of weak surface tension,subharmonic oscillations are observed.The threshold for the development of these oscillations is determined by the dimensionless acceleration of the oscillating liquid column and remains almost constant with variations in the dimensionless frequency of oscillations.At moderate values of interfacial tension(in the region of moderate dimensionless frequencies),a synchronous wave mode emerges in the stability threshold of the oscillating interface.As the dimensionless acceleration is increased further,a subharmonic mode is excited.The growth of subharmonic oscillations occurs against the background of harmonic wave oscillations,with the oscillations of the interface representing a combination of two standing waves.展开更多
LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)is an attractive material for high-energy-density Li-ion batteries in electric vehicles.However,it suffers from rapid capacity fading.Previous studies have shown that tuning the ...LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)is an attractive material for high-energy-density Li-ion batteries in electric vehicles.However,it suffers from rapid capacity fading.Previous studies have shown that tuning the positive electrode material via atomic layer deposition(ALD)can enhance the electrochemical performance of the material.In this article,we introduce a novel coating method using gaseous precursors in an ALD reactor,where an AlO_(x)layer is deposited directly on the surface of the NMC811 precursor,followed by lithiation.The AlO_(x)coating is applied to the NMC811 powder substrate by exposing it to gas-phase precursors,using a conventional ALD and simplified ALD(chemical vapor deposition-like)method.It is observed that the novel methods lead to the incorporation of Al as a dopant within the bulk of NMC811,rather than forming a conformal AlO_(x)coating,after the final lithiation step.The optimized procedures result in positive electrode materials with higher capacity and enhanced cycling stability in both half-cell and full-cell configurations.Doping or coating was shown to mitigate transition metal dissolution,reduce side reactions between the active material and electrolyte,and improve structural stability.展开更多
The gravitational memory effect manifests gravitational nonlinearity,degenerate vacua,and asymptotic symmetries;its detection is considered challenging.We propose using a space-borne interferometer to detect memory si...The gravitational memory effect manifests gravitational nonlinearity,degenerate vacua,and asymptotic symmetries;its detection is considered challenging.We propose using a space-borne interferometer to detect memory signals from stellar-mass binary black holes(BBHs),typically targeted by ground-based detectors.We use DECIGO detector as an example.Over 5 years,DECIGO is estimated to detect approximately 2,036 memory signals(SNRs>3)from stellar-mass BBHs.Simulations used frequency-domain memory waveforms for direct SNR estimation.Predictions utilized a GWTC-3 constrained BBH population model(Power law+Peak mass,DEFAULT spin,Madau-Dickinson merger rate).The analysis used conservative lower merger rate limits and considered orbital eccentricity.The high detection rate stems from strong memory signals within DECIGO’s bandwidth and the abundance of stellar-mass BBHs.This substantial and conservative detection count enables statistical use of the memory effect for fundamental physics and astrophysics.DECIGO exemplifies that space interferometers may better detect memory signals from smaller mass binaries than their typical targets.Detectors in lower frequency bands are expected to find strong memory signals from∼10^(4)M⊙binaries.展开更多
This paper investigates the influence of filling fraction on the segregation patterns of binary granular mixtures in a vertically vibrating drum through experiments and simulations.Glass and stainless steel spherical ...This paper investigates the influence of filling fraction on the segregation patterns of binary granular mixtures in a vertically vibrating drum through experiments and simulations.Glass and stainless steel spherical grains,which differ in mass density,are used to give rise to density-driven segregation.The results reveal four segregation patterns,including Brazil nut effect segregation,counterclockwise two-eye-like segregation,dumpling-like segregation and clockwise twoeye-like segregation.The theoretical analysis demonstrates that grains predominantly exhibit counterclockwise convection at low filling fractions,while clockwise convection dominates at high filling fractions.Competition between buoyancy and convection forces determines the final stable segregation pattern.These findings provide valuable insights into controlling segregation in granular systems,which is crucial for optimizing industrial processes in fields such as pharmaceuticals and chemical engineering.展开更多
Iron-chromium flow batteries(ICRFBs)have emerged as an ideal large-scale energy storage device with broad application prospects in recent years.Enhancement of the Cr^(3+)/Cr^(2+)redox reaction activity and inhibition ...Iron-chromium flow batteries(ICRFBs)have emerged as an ideal large-scale energy storage device with broad application prospects in recent years.Enhancement of the Cr^(3+)/Cr^(2+)redox reaction activity and inhibition of the hydrogen evolution side reaction(HER)are essential for the development of ICRFBs and require a novel catalyst design.However,elucidating the underlying mechanisms for modulating catalyst behaviors remains an unresolved challenge.Here,we show a novel precisely controlled preparation of a novel thermal-treated carbon cloth electrode with a uniform deposit of low-cost indium catalyst particles.The density functional theory analysis reveals the In catalyst has a significant adsorption effect on the reactants and improves the redox reaction activity of Cr^(3+)/Cr^(2+).Moreover,H+is more easily absorbed on the surface of the catalyst with a high migration energy barrier,thereby inhibiting the occurrence of HER.The assembled ICRFBs have an average energy efficiency of 83.91%at 140 mA cm^(-2),and this method minimizes the electrodeposition process and cleans the last obstacle for industry long cycle operation requirements.The ICRFBs exhibit exceptional long-term stability with an energy efficiency decay rate of 0.011%per cycle at 1000 cycles,the lowest ICRFBs reported so far.Therefore,this study provides a promising strategy for developing ICRFBs with low costs and long cycle life.展开更多
The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate incr...The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate increases.Ab initio molecular dynamics simulations demonstrate that a high heating rate induces anabatic oscillations,indicating a decrease in thermodynamic stability and a tendency for the crystal surface to undergo reconstruction.The presence of an intermediate phase at the grain boundary amplifies atomic migration-induced interface fusion and consequently augments crystal growth kinetics.However,the excessively high heating rate aggravates the Li+/Ni2+mixing in the Ni-rich cathode.The single-crystal Ni-rich cathode exhibits enhanced structural/thermal stability but a decreased specific capacity and rate performance compared with its polycrystalline counterpart.展开更多
Ohmic contacts are fundamental components in semiconductor technology,facilitating efficient electrical connection and excellent device performance.We employ first-principles calculations to show that semimetallic gra...Ohmic contacts are fundamental components in semiconductor technology,facilitating efficient electrical connection and excellent device performance.We employ first-principles calculations to show that semimetallic graphene is a natural Ohmic contact partner of monolayer semiconducting black arsenic(BAs),for which the top of the valence band is below the Fermi energy of the order of 10~2 meV.The Ohmic contact arises from the giant Stark effect induced by van der Waals electron transfer from BAs to graphene,which does not destroy their respective band features.Remarkably,we show that this intrinsic Ohmic contact remains robust across a wide range of interlayer distances(adjustable by strain)or vertical electric fields,whereas the weak spin splitting of the order of 1 meV induced by symmetry breaking plays little part in Ohmic contact.These findings reveal the potential applications of graphene–BAs in ultralow dissipation transistors.展开更多
In order to address challenges posed by the reduction in transistor size,researchers are concentrating on two-dimensional(2D)materials with high dielectric constants and large band gaps.Monoclinic ZrO_(2)(m-ZrO_(2))ha...In order to address challenges posed by the reduction in transistor size,researchers are concentrating on two-dimensional(2D)materials with high dielectric constants and large band gaps.Monoclinic ZrO_(2)(m-ZrO_(2))has emerged as a promising gate dielectric material due to its suitable dielectric constant,wide band gap,ideal valence-band offset,and good thermodynamic stability.However,current deposition methods face compatibility issues with 2D semiconductors,highlighting the need for high-quality dielectrics and interfaces.Here,high-quality 2D m-ZrO_(2)single crystals are successfully prepared using a onestep chemical vapor deposition(CVD)method,aided by 5A molecular sieves for oxygen supply.The prepared ZrO_(2)is utilized as a gate dielectric in the construction of MoS2 field-effect transistors(FETs)to investigate its electrical property.The FETs exhibit a high carrier mobility of up to 5.50 cm^(2)·V^(−1)·s^(−1),and a current switching ratio(Ion/off)of approximately 10^(4),which aligns with the current standards of logic circuits,indicating that ZrO_(2)has application value as a gate dielectric.The successful onestep preparation of single-crystal ZrO_(2)paves the way for the utilization of high-κgate dielectrics and creates favorable conditions for the development of high-performance semiconductor devices,offering new possibilities for transistor miniaturization.展开更多
Realizing the point-of-care tumor markers biodetection with good convenience and high sensitivity possesses great significance for prompting cancer monitoring and screening in biomedical study field.Herein,the quantum...Realizing the point-of-care tumor markers biodetection with good convenience and high sensitivity possesses great significance for prompting cancer monitoring and screening in biomedical study field.Herein,the quantum dots luminescence and microfluidic biochip with machine vision algorithm-based intelligent biosensing platform have been designed and manufactured for point-of-care tumor markers diagnostics.The employed quantum dots with excellent photoluminescent performance are modified with specific antibody as the optical labeling agents for the designed sandwich structure immunoassay.The corresponding biosensing investigations of the designed biodetection platform illustrate several advantages involving high sensitivity(~0.021 ng mL^(−1)),outstanding accessibility,and great integrability.Moreover,related test results of human-sourced artificial saliva samples demonstrate better detection capabilities compared with commercially utilized rapid test strips.Combining these infusive abilities,our elaborate biosensing platform is expected to exhibit potential applications for the future point-of-care tumor markers diagnostic area.展开更多
The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium he...The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium hexafluorophosphate)(PTA),and introduce it into the buried interface of PSCs.The quaternary ammonium cation(N(-CH_(3))^(3+))in PTA can fill the vacancies of organic cations within the perovskite structure and reduce shallow energy level defects.Additionally,the hexafluorophosphate(PF6−)in PTA forms a Lewis acid-base interaction with Pb^(2+)in the perovskite layer,effectively passivating deep en-ergy level defects.Furthermore,hydrogen bonding can be established between organic cations and the PF6−anion,preventing the formation of shallow energy level defects.Through this synergistic mecha-nism,the deep and shallow energy level defects are effectively mitigated,resulting in improved device performance.As a result,the resulting treated inverted PSC exhibits an impressive power conversion ef-ficiency(PCE)of 24.72%.Notably,the PTA-treated PSCs exhibit remarkable stability,with 88.5%of the original PCE retained after undergoing heat aging at 85℃ for 1078 h,and 89.1%of the initial PCE main-tained following continuous exposure to light for 1100 h at the maximum power point.Synergistically suppressing multiple defects at the buried interface through the use of polyionic liquids is a promising way to improve the commercial viability of PSCs.展开更多
Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(T...Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(TENGs)stand out as a prominent device capitalizing on the principles of triboelectrification and electrostatic induction to generate electricity or electrical signals.In efforts to augment the electrical output performance of TENGs and broaden their range of applications,researchers have endeavored to refine materials,surface morphology,and structural design.Among them,physical morphological modifications play a pivotal role in enhancing the electrical properties of TENGs by increasing the contact surface area,which can be achieved by building micro-/nano-structures on the surface or inside the friction material.In this review,we summarize the common morphologies of TENGs,categorize the morphologies into surface and internal structures,and elucidate their roles in enhancing the electric output performance of devices.Moreover,we systematically classify the methodologies employed for morphological preparation into physical and chemical approaches,thereby furnishing a comprehensive survey of the diverse techniques.Subsequently,typical applications of TENGs with special morphology divided by energy harvesting and self-powered sensors are presented.Finally,an overview of the challenges and future trajectories pertinent to TENGs is conducted.Through this endeavor,the aim of this article is to catalyze the evolution of further strategies for enhancing performance of TENGs.展开更多
Air pollution,a critical environmental issue,necessitates urgent action.It originates from both human activities,like industrial emissions and vehicle pollution,and natural events such as sandstorms,leading to increas...Air pollution,a critical environmental issue,necessitates urgent action.It originates from both human activities,like industrial emissions and vehicle pollution,and natural events such as sandstorms,leading to increased atmospheric pollutants such as sulfur dioxide(SO_(2)),nitrogen dioxide(NO_(2)),ammonia ion(NH_(4)^(+)),black carbon,ozone,and fine particulate matter(PM_(2.5)).Leveraging China's extensive air quality monitoring data,artificial intelligence(AI)was used in this study to enhance air quality prediction and management.The study aims to utilize the vast air monitoring data more effectively by developing advanced air quality assessment methods and AI models.An AI-based method presented in this study was applied to train extensive air quality data,enabling an intelligent air quality index(AQI)that swiftly and accurately reflects air quality status,to assess impacts on sensitive groups,and to predict future trends.This smart prediction and optimization(SPO)approach not only utilizes existing monitoring network data efficiently but also offers precise future air quality forecasts,providing valuable strategies for pollution prevention and air quality improvement.Data on various pollutants were collected from four regions in China between August 2021 and July 2022,using diverse modeling techniques and machine learning methodologies.The models achieved a high accuracy level of around 99%,indicating the significant portion of air quality that falls into the unhealthy category,especially impacting sensitive groups and reflecting the adverse atmospheric conditions in the studied regions.展开更多
We have investigated the magnetic, dielectric, pyroelectric, and thermal expansion properties of a layered perovskite metal–organic framework, [NH_(4)Cl]_(2)[Ni(HCOO)_(2)(NH_(3))_(2)]. The material undergoes three ph...We have investigated the magnetic, dielectric, pyroelectric, and thermal expansion properties of a layered perovskite metal–organic framework, [NH_(4)Cl]_(2)[Ni(HCOO)_(2)(NH_(3))_(2)]. The material undergoes three phase transitions including a canted antiferromagnetic transition at ~36 K, and two successive structural transitions around 100 K and 110 K, respectively. The temperature dependence of dielectric permittivity and pyroelectric current suggests that the structural transitions induce weak ferroelectricity along the c-axis and antiferroelectricity in the ab plane. A negative thermal expansion along the c-axis is observed between two structural phase transitions, which is ascribed to the abnormal shrinkage of interlayer hydrogen bonding length. Moreover, the ferroelectric/antiferroelectric phase transition temperature shifts towards a higher temperature under a magnetic field, suggesting certain magnetoelectric coupling in the paramagnetic phase. Our study suggests that the layered metal–organic frameworks provide a unique playground for exploring exotic physical properties such as multiferroicity and abnormal thermal expansion.展开更多
The attosecond extreme ultraviolet(XUV) pulse pump and femtosecond infrared(IR) pulse probe scheme is commonly used to study the dynamics and attosecond transient absorption(ATA) spectra of microscopic systems. In a r...The attosecond extreme ultraviolet(XUV) pulse pump and femtosecond infrared(IR) pulse probe scheme is commonly used to study the dynamics and attosecond transient absorption(ATA) spectra of microscopic systems. In a recent report [Proc. Natl. Acad. Sci. USA 121 e2307836121(2024)], we showed that shaped XUV pulses with spectral minima can significantly alter the absorption line shape of helium's 2s2p doubly excited state within a few tens of attoseconds.However, it remains unclear if similar effects could be observed in a singly excited state. In this study, we use shaped XUV pulses to excite helium's 2p singly excited state and couple the 2p and 3d states with a delayed IR pulse. Comparing these results with those from Gaussian XUV pulses, we find that the ATA spectra for the shaped XUV pulses exhibit more pronounced changes with delay, while the changes for the Gaussian pulses are gradual. We also explain these differences through population changes and analytical models. Our findings show that shaped XUV pulses can regulate the dynamics and absorption spectra of a singly excited state.展开更多
基金supported by the Joint Foundation of National Natural Science Foundation of China and China Academy of Engineering Physics (Grant No 10476007)the Program for New Century Excellent Talents in University (Grant No NCET-05-0799)the Program for Excellent Talents of University of Electronic Science and Technology (Grant No 23601008)
文摘The thermodynamic properties of the ε phase of solid oxygen are studied by using the analytic mean field approach （AMFP）. Analytic expressions for the Helmholtz free energy, internal energy and equation of state of solid oxygen have been derived based on the multi-exponential potential. The formulism for the case of double-exponential （DE） model is applied to the ε phase of solid oxygen. Its four potential parameters are determined through fitting the experimental compression data of the ε phase of solid oxygen. Numerical results of the pressure dependence of the volume calculated by using the AMFP are in good agreement with the original experimental data. This suggests that the AMFP is a useful approach to study the thermodynamic properties of the ε phase of solid oxygen. Furthermore, we predict the variation of the volume, lattice parameters and intermolecular distances with pressure, and some thermodynamic quantities versus volume, at several higher temperatures.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11075035 and 11222544)the Fok Ying Tung Education Foundation,China(Grant No. 131008)+2 种基金the Program for New Century Excellent Talents in University,China (Grant No. NCET-12-0121)the Shanghai Rising-Star Program,China(Grant No. 12QA1400200)the Fundamental Research Funds for the Central Universities,China
文摘It is important to know whether the laws or phenomena in statistical physics for natural systems with non-adaptive agents still hold for social human systems with adaptive agents, because this implies whether it is possible to study or understand social human systems by using statistical physics originating from natural systems. For this purpose, we review the role of human adaptability in four kinds of specific human behaviors, namely, normal behavior, herd behavior, contrarian behavior, and hedge behavior. The approach is based on controlled experiments in the framework of market-directed resource-allocation games. The role of the controlled experiments could be at least two-fold： adopting the real human decision-making process so that the system under consideration could reflect the performance of genuine human beings; making it possible to obtain macroscopic physical properties of a human system by tuning a particular factor of the system, thus directly revealing cause and effect. As a result, both computer simulations and theoretical analyses help to show a few counterparts of some laws or phenomena in statistical physics for social human systems： two-phase phenomena or phase transitions, entropy-related phenomena, and a non-equilibrium steady state. This review highlights the role of human adaptability in these counterparts, and makes it possible to study or understand some particular social human systems by means of statistical physics coming from natural systems.
文摘Since the first demonstrations of nuclear magnetic resonance (NMR) in condensed matter in 1946, the field of NMR has yielded a continuous flow of conceptual advances and methodological innovations that continues today. Much progress has been made in the utilization of solid-state NMR to illuminate molecular structure and dynamics in systems not controllable by any other way. NMR deals with time-dependent perturbations of nuclear spin systems and solving the time-dependent Schrodinger equation is a central problem in quantum physics in general and solid-state NMR in particular. This theoretical perspective outlines the methods used to treat theoretical problems in solid-state NMR as well as the recent theoretical development of spin dynamics in NMR and physics. The purpose of this review is to unravel the versatility of theories in solid-state NMR and to present the recent theoretical developments of spin dynamics.
文摘We study theoretically the electron transport properties in achiral carbon nanotubes under the influence of an external electric field E(t) using Boltzmann’s transport equation to derive the current-density. A negative differential conductivity (NDC) is predicted in quasi-static approximation i.e., ωτ 0 is equal to the amplitude of the AC electric field E1. The peak of the NDC intensity occurs at very weaker fields than that of superlattice under the same conditions. The peak intensity decreases and shifts to right with the increase in the amplitude of the ac field. This mechanism suppresses the domain formation and therefore could be used in terahertz frequency generation.
基金funded by the Science and Technology Project of Tianjin(No.24YDTPJC00680)the National Natural Science Foundation of China(No.52406191).
文摘The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods to address the cooling challenge for high-power devices in DCs.Hybrid nanofluid(HNF)has the advantages of high thermal conductivity and good rheological properties.This study summarizes the numerical investigations of HNFs in mini/micro heat sinks,including the numerical methods,hydrothermal characteristics,and enhanced heat transfer technologies.The innovations of this paper include:(1)the characteristics,applicable conditions,and scenarios of each theoretical method and numerical method are clarified;(2)the molecular dynamics(MD)simulation can reveal the synergy effect,micro motion,and agglomeration morphology of different nanoparticles.Machine learning(ML)presents a feasiblemethod for parameter prediction,which provides the opportunity for the intelligent regulation of the thermal performance of HNFs;(3)the HNFs flowboiling and the synergy of passive and active technologies may further improve the overall efficiency of liquid cooling systems in DCs.This review provides valuable insights and references for exploring the multi-phase flow and heat transport mechanisms of HNFs,and promoting the practical application of HNFs in chip-level liquid cooling in DCs.
基金financial support from the National Natural Science Foundation of China(Grant No.61971201)。
文摘High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-corrected transmission electron microscopy constrain resolution.A machine learning algorithm is developed to determine the aberration parameters with higher precision from small,lattice-periodic crystal images.The proposed algorithm is then validated with simulated HRTEM images of graphene and applied to the experimental images of a molybdenum disulfide(MoS_(2))monolayer with 25 variables(14 aberrations)resolved in wide ranges.Using these measured parameters,the phases of the exit-wave functions are reconstructed for each image in a focal series of MoS_(2)monolayers.The images were acquired due to the unexpected movement of the specimen holder.Four-dimensional data extraction reveals time-varying atomic structures and ripple.In particular,the atomic evolution of the sulfur-vacancy point and line defects,as well as the edge structure near the amorphous,is visualized as the resolution has been improved from about 1.75?to 0.9 A.This method can help salvage important transmission electron microscope images and is beneficial for the images obtained from electron microscopes with average stability.
基金supported by the Ministry of Education of the Russian Federation(Project No.1023032300071-6-2.3.1).
文摘An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as the amplitude of the liquid column oscillations increases,parametric oscillations of the interface are excited in the form of a standing wave located in the channel plane.In particular,depending on the interfacial tension,the standing waves have a frequency equal to that of liquid piston oscillations(harmonic response),or half of the frequency of oscillations of the liquid column in the channel(subharmonic response).The detected type of instability has a gravitational-capillary nature and is analogous to Faraday waves.The analysis of the overcritical dynamics of wave oscillations indicates that interfacial tension plays a crucial role in determining the type of parametric instability.At high interfacial tension,only synchronous(harmonic)wave modes are observed,and the threshold of the wave excitation is determined by the amplitude of piston oscillations of the liquid column.In this case,the oscillation acceleration does not play a role and has a small value in the threshold of the synchronous mode response.In the case of weak surface tension,subharmonic oscillations are observed.The threshold for the development of these oscillations is determined by the dimensionless acceleration of the oscillating liquid column and remains almost constant with variations in the dimensionless frequency of oscillations.At moderate values of interfacial tension(in the region of moderate dimensionless frequencies),a synchronous wave mode emerges in the stability threshold of the oscillating interface.As the dimensionless acceleration is increased further,a subharmonic mode is excited.The growth of subharmonic oscillations occurs against the background of harmonic wave oscillations,with the oscillations of the interface representing a combination of two standing waves.
基金the European Union,the SOLiD project(grant agreement no.101069505),for the financial support。
文摘LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)is an attractive material for high-energy-density Li-ion batteries in electric vehicles.However,it suffers from rapid capacity fading.Previous studies have shown that tuning the positive electrode material via atomic layer deposition(ALD)can enhance the electrochemical performance of the material.In this article,we introduce a novel coating method using gaseous precursors in an ALD reactor,where an AlO_(x)layer is deposited directly on the surface of the NMC811 precursor,followed by lithiation.The AlO_(x)coating is applied to the NMC811 powder substrate by exposing it to gas-phase precursors,using a conventional ALD and simplified ALD(chemical vapor deposition-like)method.It is observed that the novel methods lead to the incorporation of Al as a dopant within the bulk of NMC811,rather than forming a conformal AlO_(x)coating,after the final lithiation step.The optimized procedures result in positive electrode materials with higher capacity and enhanced cycling stability in both half-cell and full-cell configurations.Doping or coating was shown to mitigate transition metal dissolution,reduce side reactions between the active material and electrolyte,and improve structural stability.
基金supported by the National Natural Science Foundation of China(Grant Nos.11633001,11920101003,and 12205222 for S.H.)the Key Program of the National Natural Science Foundation of China(Grant No.12433001)+1 种基金the Strate-gic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23000000)the National Key Research and Development Program of China(Grant No.2021YFC2203001 for Z.C.Z.).
文摘The gravitational memory effect manifests gravitational nonlinearity,degenerate vacua,and asymptotic symmetries;its detection is considered challenging.We propose using a space-borne interferometer to detect memory signals from stellar-mass binary black holes(BBHs),typically targeted by ground-based detectors.We use DECIGO detector as an example.Over 5 years,DECIGO is estimated to detect approximately 2,036 memory signals(SNRs>3)from stellar-mass BBHs.Simulations used frequency-domain memory waveforms for direct SNR estimation.Predictions utilized a GWTC-3 constrained BBH population model(Power law+Peak mass,DEFAULT spin,Madau-Dickinson merger rate).The analysis used conservative lower merger rate limits and considered orbital eccentricity.The high detection rate stems from strong memory signals within DECIGO’s bandwidth and the abundance of stellar-mass BBHs.This substantial and conservative detection count enables statistical use of the memory effect for fundamental physics and astrophysics.DECIGO exemplifies that space interferometers may better detect memory signals from smaller mass binaries than their typical targets.Detectors in lower frequency bands are expected to find strong memory signals from∼10^(4)M⊙binaries.
基金supported by the National Natural Science Foundation of China(Grant No.11574153)the Fund of No.TSXK2022D007。
文摘This paper investigates the influence of filling fraction on the segregation patterns of binary granular mixtures in a vertically vibrating drum through experiments and simulations.Glass and stainless steel spherical grains,which differ in mass density,are used to give rise to density-driven segregation.The results reveal four segregation patterns,including Brazil nut effect segregation,counterclockwise two-eye-like segregation,dumpling-like segregation and clockwise twoeye-like segregation.The theoretical analysis demonstrates that grains predominantly exhibit counterclockwise convection at low filling fractions,while clockwise convection dominates at high filling fractions.Competition between buoyancy and convection forces determines the final stable segregation pattern.These findings provide valuable insights into controlling segregation in granular systems,which is crucial for optimizing industrial processes in fields such as pharmaceuticals and chemical engineering.
基金support from the National Natural Science Foundation of China(No.22308378,22308380,22393963)the Science Foundation of China University of Petroleum,Beijing(No.2462023XKBH005,ZX20230078).
文摘Iron-chromium flow batteries(ICRFBs)have emerged as an ideal large-scale energy storage device with broad application prospects in recent years.Enhancement of the Cr^(3+)/Cr^(2+)redox reaction activity and inhibition of the hydrogen evolution side reaction(HER)are essential for the development of ICRFBs and require a novel catalyst design.However,elucidating the underlying mechanisms for modulating catalyst behaviors remains an unresolved challenge.Here,we show a novel precisely controlled preparation of a novel thermal-treated carbon cloth electrode with a uniform deposit of low-cost indium catalyst particles.The density functional theory analysis reveals the In catalyst has a significant adsorption effect on the reactants and improves the redox reaction activity of Cr^(3+)/Cr^(2+).Moreover,H+is more easily absorbed on the surface of the catalyst with a high migration energy barrier,thereby inhibiting the occurrence of HER.The assembled ICRFBs have an average energy efficiency of 83.91%at 140 mA cm^(-2),and this method minimizes the electrodeposition process and cleans the last obstacle for industry long cycle operation requirements.The ICRFBs exhibit exceptional long-term stability with an energy efficiency decay rate of 0.011%per cycle at 1000 cycles,the lowest ICRFBs reported so far.Therefore,this study provides a promising strategy for developing ICRFBs with low costs and long cycle life.
基金funded by the National Natural Science Foundation of China(No.22379052)Taishan Scholars of Shandong Province,China(No.tsqnz20221143)。
文摘The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate increases.Ab initio molecular dynamics simulations demonstrate that a high heating rate induces anabatic oscillations,indicating a decrease in thermodynamic stability and a tendency for the crystal surface to undergo reconstruction.The presence of an intermediate phase at the grain boundary amplifies atomic migration-induced interface fusion and consequently augments crystal growth kinetics.However,the excessively high heating rate aggravates the Li+/Ni2+mixing in the Ni-rich cathode.The single-crystal Ni-rich cathode exhibits enhanced structural/thermal stability but a decreased specific capacity and rate performance compared with its polycrystalline counterpart.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62374088 and 12074193)。
文摘Ohmic contacts are fundamental components in semiconductor technology,facilitating efficient electrical connection and excellent device performance.We employ first-principles calculations to show that semimetallic graphene is a natural Ohmic contact partner of monolayer semiconducting black arsenic(BAs),for which the top of the valence band is below the Fermi energy of the order of 10~2 meV.The Ohmic contact arises from the giant Stark effect induced by van der Waals electron transfer from BAs to graphene,which does not destroy their respective band features.Remarkably,we show that this intrinsic Ohmic contact remains robust across a wide range of interlayer distances(adjustable by strain)or vertical electric fields,whereas the weak spin splitting of the order of 1 meV induced by symmetry breaking plays little part in Ohmic contact.These findings reveal the potential applications of graphene–BAs in ultralow dissipation transistors.
基金support from the National Natural Science Foundation of China(No.21975067)Shenzhen Science and Technology Program(No.JCYJ20220530160407016).
文摘In order to address challenges posed by the reduction in transistor size,researchers are concentrating on two-dimensional(2D)materials with high dielectric constants and large band gaps.Monoclinic ZrO_(2)(m-ZrO_(2))has emerged as a promising gate dielectric material due to its suitable dielectric constant,wide band gap,ideal valence-band offset,and good thermodynamic stability.However,current deposition methods face compatibility issues with 2D semiconductors,highlighting the need for high-quality dielectrics and interfaces.Here,high-quality 2D m-ZrO_(2)single crystals are successfully prepared using a onestep chemical vapor deposition(CVD)method,aided by 5A molecular sieves for oxygen supply.The prepared ZrO_(2)is utilized as a gate dielectric in the construction of MoS2 field-effect transistors(FETs)to investigate its electrical property.The FETs exhibit a high carrier mobility of up to 5.50 cm^(2)·V^(−1)·s^(−1),and a current switching ratio(Ion/off)of approximately 10^(4),which aligns with the current standards of logic circuits,indicating that ZrO_(2)has application value as a gate dielectric.The successful onestep preparation of single-crystal ZrO_(2)paves the way for the utilization of high-κgate dielectrics and creates favorable conditions for the development of high-performance semiconductor devices,offering new possibilities for transistor miniaturization.
基金supported by grants from the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.CRF No.PolyU C5110-20G)PolyU Grants(1-CE0H,1-W30M,1-CD4S).
文摘Realizing the point-of-care tumor markers biodetection with good convenience and high sensitivity possesses great significance for prompting cancer monitoring and screening in biomedical study field.Herein,the quantum dots luminescence and microfluidic biochip with machine vision algorithm-based intelligent biosensing platform have been designed and manufactured for point-of-care tumor markers diagnostics.The employed quantum dots with excellent photoluminescent performance are modified with specific antibody as the optical labeling agents for the designed sandwich structure immunoassay.The corresponding biosensing investigations of the designed biodetection platform illustrate several advantages involving high sensitivity(~0.021 ng mL^(−1)),outstanding accessibility,and great integrability.Moreover,related test results of human-sourced artificial saliva samples demonstrate better detection capabilities compared with commercially utilized rapid test strips.Combining these infusive abilities,our elaborate biosensing platform is expected to exhibit potential applications for the future point-of-care tumor markers diagnostic area.
基金supported by the Science,Technology,and Innovation Commission of Shenzhen Municipality(No.GJHZ20220913143204008)the Shccig-Qinling Program(No.SMYJY202300294C)+3 种基金National Natural Science Foundation of China(Nos.22261142666,52372225,52172237,22305191)the Shaanxi Science Fund for Distinguished Young Scholars(No.2022JC-21)the Research Fund of the State Key Laboratory of Solidification Processing(NPU)China(No.2021-QZ-02).
文摘The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium hexafluorophosphate)(PTA),and introduce it into the buried interface of PSCs.The quaternary ammonium cation(N(-CH_(3))^(3+))in PTA can fill the vacancies of organic cations within the perovskite structure and reduce shallow energy level defects.Additionally,the hexafluorophosphate(PF6−)in PTA forms a Lewis acid-base interaction with Pb^(2+)in the perovskite layer,effectively passivating deep en-ergy level defects.Furthermore,hydrogen bonding can be established between organic cations and the PF6−anion,preventing the formation of shallow energy level defects.Through this synergistic mecha-nism,the deep and shallow energy level defects are effectively mitigated,resulting in improved device performance.As a result,the resulting treated inverted PSC exhibits an impressive power conversion ef-ficiency(PCE)of 24.72%.Notably,the PTA-treated PSCs exhibit remarkable stability,with 88.5%of the original PCE retained after undergoing heat aging at 85℃ for 1078 h,and 89.1%of the initial PCE main-tained following continuous exposure to light for 1100 h at the maximum power point.Synergistically suppressing multiple defects at the buried interface through the use of polyionic liquids is a promising way to improve the commercial viability of PSCs.
基金financially supported by the Natural Science Foundation of Guangdong Province(No.2024A1515010639)PolyU Postdoc Matching Fund Scheme(No.1-W327),PolyU Grant(No.1-CE0H)+3 种基金Shenzhen Science and Technology Program(No.ZDSYS20220606100406016)Shenzhen Key Laboratory of Photonics and Biophotonics(No.ZDSYS20210623092006020)National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment(Shenzhen)(No.868-000003010103)National Natural Science Foundation of China(No.52208272)。
文摘Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(TENGs)stand out as a prominent device capitalizing on the principles of triboelectrification and electrostatic induction to generate electricity or electrical signals.In efforts to augment the electrical output performance of TENGs and broaden their range of applications,researchers have endeavored to refine materials,surface morphology,and structural design.Among them,physical morphological modifications play a pivotal role in enhancing the electrical properties of TENGs by increasing the contact surface area,which can be achieved by building micro-/nano-structures on the surface or inside the friction material.In this review,we summarize the common morphologies of TENGs,categorize the morphologies into surface and internal structures,and elucidate their roles in enhancing the electric output performance of devices.Moreover,we systematically classify the methodologies employed for morphological preparation into physical and chemical approaches,thereby furnishing a comprehensive survey of the diverse techniques.Subsequently,typical applications of TENGs with special morphology divided by energy harvesting and self-powered sensors are presented.Finally,an overview of the challenges and future trajectories pertinent to TENGs is conducted.Through this endeavor,the aim of this article is to catalyze the evolution of further strategies for enhancing performance of TENGs.
基金supported by the National Key R&D Program of China(No.2023YFC3707201)the National Natural Science Foundation of China(No.52320105003)+2 种基金the Informatization Plan of Chinese Academy of Sciences(No.CASWX2023PY-0103)CAS-ANSO Co-funding Research Project(No.CAS-ANSO-CF-2024)the Fundamental Research Funds for the Central Universities(No.E3ET1803)。
文摘Air pollution,a critical environmental issue,necessitates urgent action.It originates from both human activities,like industrial emissions and vehicle pollution,and natural events such as sandstorms,leading to increased atmospheric pollutants such as sulfur dioxide(SO_(2)),nitrogen dioxide(NO_(2)),ammonia ion(NH_(4)^(+)),black carbon,ozone,and fine particulate matter(PM_(2.5)).Leveraging China's extensive air quality monitoring data,artificial intelligence(AI)was used in this study to enhance air quality prediction and management.The study aims to utilize the vast air monitoring data more effectively by developing advanced air quality assessment methods and AI models.An AI-based method presented in this study was applied to train extensive air quality data,enabling an intelligent air quality index(AQI)that swiftly and accurately reflects air quality status,to assess impacts on sensitive groups,and to predict future trends.This smart prediction and optimization(SPO)approach not only utilizes existing monitoring network data efficiently but also offers precise future air quality forecasts,providing valuable strategies for pollution prevention and air quality improvement.Data on various pollutants were collected from four regions in China between August 2021 and July 2022,using diverse modeling techniques and machine learning methodologies.The models achieved a high accuracy level of around 99%,indicating the significant portion of air quality that falls into the unhealthy category,especially impacting sensitive groups and reflecting the adverse atmospheric conditions in the studied regions.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2021YFA1400303)the National Natural Science Foundation of China (Grant No. 12227806)。
文摘We have investigated the magnetic, dielectric, pyroelectric, and thermal expansion properties of a layered perovskite metal–organic framework, [NH_(4)Cl]_(2)[Ni(HCOO)_(2)(NH_(3))_(2)]. The material undergoes three phase transitions including a canted antiferromagnetic transition at ~36 K, and two successive structural transitions around 100 K and 110 K, respectively. The temperature dependence of dielectric permittivity and pyroelectric current suggests that the structural transitions induce weak ferroelectricity along the c-axis and antiferroelectricity in the ab plane. A negative thermal expansion along the c-axis is observed between two structural phase transitions, which is ascribed to the abnormal shrinkage of interlayer hydrogen bonding length. Moreover, the ferroelectric/antiferroelectric phase transition temperature shifts towards a higher temperature under a magnetic field, suggesting certain magnetoelectric coupling in the paramagnetic phase. Our study suggests that the layered metal–organic frameworks provide a unique playground for exploring exotic physical properties such as multiferroicity and abnormal thermal expansion.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12274230)the Funding of Nanjing University of Science and Technology (Grant No. TSXK2022D005)。
文摘The attosecond extreme ultraviolet(XUV) pulse pump and femtosecond infrared(IR) pulse probe scheme is commonly used to study the dynamics and attosecond transient absorption(ATA) spectra of microscopic systems. In a recent report [Proc. Natl. Acad. Sci. USA 121 e2307836121(2024)], we showed that shaped XUV pulses with spectral minima can significantly alter the absorption line shape of helium's 2s2p doubly excited state within a few tens of attoseconds.However, it remains unclear if similar effects could be observed in a singly excited state. In this study, we use shaped XUV pulses to excite helium's 2p singly excited state and couple the 2p and 3d states with a delayed IR pulse. Comparing these results with those from Gaussian XUV pulses, we find that the ATA spectra for the shaped XUV pulses exhibit more pronounced changes with delay, while the changes for the Gaussian pulses are gradual. We also explain these differences through population changes and analytical models. Our findings show that shaped XUV pulses can regulate the dynamics and absorption spectra of a singly excited state.
